Process and composition for chromizing 400-series stainless steels
US6387194B1 · kind B1 · utility
7Cited by
6References
9Claims
0Family size
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Key dates
| Filing date | Feb 20, 2001 |
| Grant date | May 14, 2002 |
| Priority date | — |
| Expiry date | Feb 20, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C12/02
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An improved process for chromizing and chrome-siliconizing 400-series stainless steel components, and in particular, 430 stainless steel components, such as boiler panel studs. The process includes the addition of between 0.12%-0.25% by weight of calcium fluoride salt to the conventional 4% by weight of ammonium chloride activator salt to the coating composition used in known diffusion coating processes. In a more preferred embodiment, small amounts of silicon powder, such as between about 0.12%-0.25% by weight, are added to the two salts and the diffusion coating material. A coating composition is provided as well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.